Fully halogenated chlorofluorinated hydrocarbons (CFCs), in particular 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113), were widely used as solvents in industry for degreasing and cleaning various surfaces, particularly for solid components of complicated shape which are difficult to clean. In addition to their use in electronics in cleaning soldering fluxes in order to remove the pickling flux which adheres to printed circuits, they were also conventionally used for degreasing metal components or for cleaning mechanical components of high quality and of high precision. In these various applications, CFC-113 was most often used in combination with other organic solvents, preferably in the form of azeotropic or pseudoazeotropic compositions having substantially the same composition in the vapor phase and in the liquid phase, so that they could be easily employed at reflux. For example, CFC-113 was used in combination with trans-1,2-dichloroethylene in compositions formerly known as Freon® MCA and Freon® SMT. Such compositions could be used as cleaning agents in the refrigeration industry.
Compositions based on CFC-113 were also conventionally used as desiccating agents, in order to remove the water adsorbed at the surface of solid components.
However, CFC-113, as well as other fully halogenated chlorofluoroalkanes, was suspected of being involved in the destruction of the stratospheric ozone layer. Consequently, new compositions which do not have a harmful influence on the ozone layer were proposed, for example, a certain number of azeotropic compositions based on hydrofluoroalkanes. In particular, Patent Application EP-A-0,512,885 (Elf Atochem) proposes an azeotropic composition comprising, by weight, 93 to 99% of 1,1,1,3,3-pentafluorobutane (HFA-365mfc) and from 7 to 1% of methanol. The patent applications JP 5/168805 and JP/5/171190 describe cleaning compositions based on HFC-365mfc and trans-1,2-dichloroethylene in proportions for which they do not from an azeotrope. EP patent application EP-A-0 653484 discloses compositions comprising 1,1,1,3,3-pentafluorobutane, trans-1,2-dichloroethylene and optionally an alcohol with 1 to 3 carbon atoms. Both trans-1,2-dichloroethylene and alcohols with 1 to 3 carbon atoms are, per se, flammable.
U.S. Pat. No. 5,714,298 discloses toner fixing agents containing HFC-365mfc and, i.a., trans-1,2-dichloro-ethylene. It is stated in table II of that patent that a mixture consisting of 70% by weight of HFC-365mfc and 30% by weight of trans-1,2-dichloroethylene, has no closed cup flash point in the range of −30° C. to +40° C. Consequently, that statement made 1996 does not exclude the possibility that a flash point exists at a higher temperature than that tested in that example; especially if it is taken into consideration that, while at the time of filing of that patent, it was believed that HFC-365mfc was non-flammable. It was later considered flammable (see, for example, U.S. Pat. No. 6,080,799) even though it can be ignited only with difficulty because it needs a high ignition energy.
EP-A-0 618288 discloses compositions comprising HFC-365mfc and ethanol which are suitable as cleaning or degreasing agents.